Does inbreeding lead to decreased human fertility?

  title={Does inbreeding lead to decreased human fertility?},
  author={Alan H. Bittles and John C. Grant and Sheena G. Sullivan and Rafat Hussain},
  journal={Annals of Human Biology},
  pages={111 - 130}
In most Western countries there is a widespread belief, fostered in part by historical prejudice and religious proscription, that inbreeding in human populations causes a reduction in fertility. Support for this belief has been claimed in HLA-based studies, with increased rates of fetal losses suggested in HLA-compatible unions. To critically assess the overall status of fertility in consanguineous unions, data on 30 populations resident in six countries were collated from a systematic review… 

Consanguinity, human evolution, and complex diseases

A range of primarily social factors, including urbanization, improved female education, and smaller family sizes indicate that the global prevalence of consanguineous unions will decline, which will initially result in decreased homozygosity, accompanied by a reduction in the expression of recessive single-gene disorders.

Impact of inbreeding on fertility in a pre-industrial population

It is suggested that inbreeding depression affects reproduction in modern societies through an interaction with age, as compared with the first half of their reproductive period.


  • V. Fuster
  • Biology
    Journal of Biosocial Science
  • 2002
Information from 1503 reconstituted families shows that complete fertility was slightly higher among consanguineous families despite a greater infant mortality, which could explain the above results.

Reproductive pattern in consanguineous and non-consanguineous marriages in La Cabrera, Spain

In the La Cabrera population, consanguinity appears as a socio-cultural process that affects the reproductive dynamic and modifies the marital structure and alters the reproductive pattern, prolonging the reproductive period, which results in a greater number of offspring.

Consanguineous marriage and human evolution.

This work has indicated that the shift from consanguineous marriage to panmixia has been accompanied by a reduction in homozygosity, and predicted decrease in incidence of both recessive single-gene disorders and more common adult-onset diseases.

Associations of autozygosity with a broad range of human phenotypes

The authors show that a genomic inbreeding coefficient (FROH) is associated with disadvantageous outcomes in 32 out of 100 traits tested, suggesting that genetic variants associated with inbreeding depression are predominantly rare.

Consanguineous marriage and childhood health

  • A. Bittles
  • Psychology
    Developmental medicine and child neurology
  • 2003
The aims of this annotation are to review briefly the current global prevalence of consanguineous marriage and to estimate and describe the deleterious outcomes expressed in the early years of life.

Assessment of association between consanguinity and fertility in Asian populations.

The association between consanguinity and fertility was assessed reviewing published literature and analyzing demographic and health survey data from Pakistan and India, showing higher fertility among women in the first-cousin unions compared to those married to non-relatives.

A review of the reproductive consequences of consanguinity.




Inbreeding effects on fertility and sterility: a case-control study in Saguenay-Lac-Saint-Jean (Québec, Canada) based on a population registry 1838-1971.

Effects of inbreeding on couples' fertility and primary sterility were investigated in five marriages between uncle and niece, 251 marriages between first-degree cousins, and 358 marriages between

The effect of parental consanguinity and inbreeding in Hirado, Japan

It is suggested that on Hirado the increased reproductivity of the consanguineous marriage largely offsets the increased mortality among the issue from such unions, and thereby dampens the rate of elimination of deleterious genes and the loss of genetic variability.

The effects of parental consanguinity and inbreeding in Hirado, Japan. I. Stillbirths and prereproductive mortality.

Evidence from domestic animals suggests inbreeding effects, at least with respect to early mortality, may be equal to consanguinity effects, and this and other papers in this series will present data in an attempt to analyze this latter category.

Reproductive behavior and health in consanguineous marriages

In many regions of Asia and Africa, consanguineous marriages currently account for approximately 20 to 50% of all unions, and preliminary observations indicate that migrants from these areas continue

Effects of consanguineous marriage on reproductive outcome in an Arab community in Israel.

A prominent public health problem associated with consanguineous marriage in the Arab community and a need for specific genetic counselling are indicated.

Inbreeding effects on fertility in humans: evidence for reproductive compensation.

The effects of inbreeding on fertility among inbred adult Hutterites is investigated and significantly reduced fecundity among the most inbred Hutterite women, as evidenced by longer interbirth intervals and longer intervals to a recognized pregnancy, which suggest the presence of recessive alleles that adversely affect fertility among the population.

Consanguinity as a determinant of reproductive behaviour and mortality in Pakistan.

Unions between close biological relatives were characterized by younger maternal and paternal ages at marriage and reduced spousal age difference, but a longer time to first delivery, but overall, they exhibited greater fertility than non-consanguineous couples.

Consanguinity, spousal age at marriage and fertility in seven Pakistani Punjab cities.

A retrospective study was conducted on spousal age at marriage, time to first birth and total pregnancies in the populations of seven cities in the Pakistani province of Punjab. Consanguineous

Inbreeding effects on reproductive outcome: a study based on a large sample from the endogamous Vadde of Kolleru Lake, Andhra Pradesh, India.

The average B value and the number of lethal equivalents found for the highly inbred southern Indian populations in general and for the Vadde in particular were much smaller than those from other parts of the world, providing empirical support to Sanghvi's hypothesis on long-term effects of inbreeding.

Empirical estimates of the global prevalence of consanguineous marriage in contemporary societies

A detailed and comprehensive review of the current global prevalence of consanguineous marriages, based almost exclusively on data collated from refereed journal articles, supplemented where appropriate by information from edited book chapters, papers submitted for publication and personal communications.